From a casting agent’s perspective, Matt Damon and Leonardo DiCaprio are as good as it gets. Not only can they both carry a movie, but they immerse themselves totally in their parts. Both, too, have displayed an impressive range: Damon can play an amnesiac superspy (The Bourne Identity) as convincingly as a slap-happy Siamese twin (Stuck on You), and Leo can embody a mentally retarded teen with the same ease as he can Howard Hughes (The Aviator). Finally, both have shown a willingness to learn accents, which opens up a slew of casting possibilities. The question is, which one has a better knack for it? If said agent were casting the part of a lisping Tasmanian eunuch, for instance, which actor would he rely on to nail the inflections?

There are two particularly tricky accents we can compare them on: South African—which Damon uses in Clint Eastwood’s politico-rugby drama Invictus and DiCaprio learned for 2006’s The Blood Diamond—and South Boston, which both actors pulled off for Martin Scorsese’s The Departed, in a mano-a-mano dialect duel.

I called on two friends to help me judge. The first is Ryan, a lawyer from Johannesburg. I showed him the above trailer for Invictus and the below trailer for Blood Diamond. Ryan’s thorough analysis after the jump.

As far as their accents go, I don’t really think it’s close—Leo is just unbelievable. Although he’s not perfect, I could believe that he was a South African (he plays a Zimbabwean [inThe Blood Diamond], but the accents can be the same). Matt Damon isn’t bad, but it sounds like someone doing an accent more than sounding like a South African. While Leo consistently gets every word right, Matt Damon gets the central words right—for example, at 1:00 in Invictus the “invited” is really good. So it doesn’t really matter that the other words are not perfect. But Leo goes for every word—e.g. at 0:45 in The Blood Diamondtrailer, every word is correct except “here” (he overpronounces the “r”), and at 0:55 everything is correct except “told” (it’s too British). At 1:17 in theInvictus*trailer, meanwhile, I am not convinced that any of the words are correct except “win”—but that’s the central word so he sounds fine.

Another difference between the two is that Leo is doing the accent of an English-speaking South African speaking English, while Matt Damon is doing the accent of an Afrikaans-speaking South African speaking English. So at 2:07 inInvictus,when he says “tiny,” that’s a pretty good Afrikaaner accent, but I, for example, do not pronounce “tiny” like that at all. We also have the accent of indigenous language–speaking South Africans speaking English, which sounds like that guy at 1:30 in>Invictus(that guy is actually South African so he sounds perfect).*

Meanwhile, I asked dyed-in-the-wool Irish-Bostonian Joe Hickey, a curator and factotum extraordinaire, what he made of DiCaprio and Damon’s Southie accents. His answer was more concise, and confusing, than Ryan’s, but he reached a similar conclusion (which is surprising, since Damon is a Boston native):

Even though Damon is from here, his accent inThe Departedsounded nothing like it did inGood Will Hunting. Everyone I know thought DiCaprio’s Bawstin accent was much better than Damon’s.

For reference, here’s the Departed trailer:

So Leo has the edge on accents, barely. But as Sean Connery has proven time and time again—be it with his Scots-inflected Russian rumble in The Hunt for the Red October or his Scots-inflected Irish brogue in Darby Gill in the Little People—it’s not all about the accents and voices. Otherwise, Frank Caliendo would be getting an Oscar.